The present invention relates to intravascular catheter apparatus in general and in particular to an intravascular catheter apparatus with a coaxial puncturing member, a sealing member for removably receiving the puncturing member and an integral infusion member for connecting an external infusion apparatus or the like to the catheter prior to its insertion in a body.
In applicant's U.S. Pat. No. 3,313,299 there is disclosed an intravascular catheter with a coaxial puncturing means. In the catheter disclosed there is provided a hub member. Extending from the hub member and a passageway located therein there is provided a canula. The puncturing means is provided for inserting the canula in a body. At the opposite end of the hub member there is provided a resilient sealing means. The sealing means is provided for removably receiving the puncturing means. Extending at an angle from the hub member and the passageway in the hub member there is provided an integral infusion connecting means forming a side passageway for connecting the catheter to an external infusion apparatus or the like.
In use, infusion apparatus is connected to the side passageway prior to the insertion of the canula in the body with the puncturing means. After the infusion apparatus is connected to the catheter and the canula is inserted in the body with the puncturing means, the puncturing means is removed from the canula, the hub member and the sealing means. Ordinarily, the sealing means, being a resilient member, closes tightly after the puncturing means is removed therefrom for preventing a flow of fluid from the catheter through the sealing means.
While fluid flow through the sealing means is generally prevented from occurring by the resilient nature of the sealing means, it has been found that when the puncturing means is left in the sealing means for a long period of time, as during shipping and storing of the catheters prior to their use, the material of the resilient sealing means sometimes becomes permanently deformed. When the sealing means becomes permanently deformed, a hole created in the sealing means by the puncturing means does not close or is easily forced open by internal pressures after the puncturing means is removed therefrom.
In applicant's U.S. Pat. No. 3,853,127, there is disclosed a plurality of embodiments of an improved elastic sealing member proposed for use in the intravascular catheter disclosed in applicant's U.S. Pat. No. 3,313,299.
In all of the embodiments disclosed in applicant's U.S. Pat. No. 3,853,127 there is provided a means for generating a nonuniform stress in an elastic sealing member in a plane substantially normal to the longitudinal axis of penetration of the sealing member by a puncturing means. The stress is generated by utilizing a sealing member having a first surface of a first configuration for sealing against a second surface having a second configuration. For use in or about a passageway having a walled surface configuration closely identical to that of a facing surface of a sealing member, a sleeve having a different surface configuration is used between the sealing member and the walled surface.
The fabrication of the catheters disclosed in applicant's U.S. Pat. No. 3,313,299 and applicant's U.S. Pat. No. 3,853,127 typically requires the use of molding equipment employing one or more slides. The fabrication of the unusual geometric shapes employed in the embodiments of the sealing member of applicant's U.S. Pat. No. 3,853,127 also requires relatively time consuming machining of the mold parts. Together, the use of molding apparatus requiring slides and the irregularly shaped curved surfaces of the molds, results in a relatively long cycle time, reduces mold capacity and increases part cost.
Still another disadvantage of prior known catheters of the type disclosed in applicant's prior patent involves the low friction nature of the material typically used in the fabrication of the hubs. Because of the low friction nature of the material used in the hubs, the retention of a member in the hubs which is typically used for connecting external infusion apparatus and the like to the catheter is often difficult. This is because there is a tendency for the connecting member to slide from the hub during normal handling.